1. Field of the Invention
This invention relates to an implant for an injured tendon of a digitus manus into inside of which an injured tendon of a digitus manus is inserted and passed through so as to function for suture and cure of the injured tendon, and for convalescence such as preventing the sutured tendon from coalescing with a living organism surrounding the sutured tendon.
2. Discussion of the Relevant Art
Tendon injuries (cut off or damaged) of a digitus manus happens daily such as during working or exercising although a degree of the injuries varies. When a tendon of a digitus manus is injured, basically it is important to treat, namely, to suture the injured tendon as fast as possible after getting injured. And this primary treatment will affect greatly on its convalescence. During the process of healing not only the amputated tendon conglutinates but also the sutured portion of the tendon coalesces with its ambient tissue of the living organism, thereby to bring about dysfunction. This makes it difficult to conduct an operation to suture an injured tendon. The injury of a flexor tendon, especially a portion called "the Zone 2" is a top problem to be solved.
With the recent progress of the orthopaedic surgery, various methods of suturing operation have been studied and developed as shown in FIGS. 10 and 11. More concretely, as a conventional method of suturing operation there is Verdon's suture method (FIG. 10A). This method is to make both ends K1, K2 of an amputated tendon abutting contact with each other and to suture several points around the abutting contact face. A method for more steady suture is Kieinert's suture method (FIG. 10B). This method is to cross a stitch to suture both ends K1, K2 of the amputated tendon. Bunuell's suture method shown in FIG. 10C is to make both ends K1, K2 of the amputated tendon abutting contact with each other, to suture the amputated tendon with a stitch penetrating through two points of upper and under of the center of the abutting contact face perpendicularly, and to cross the stitch like the above-mentioned Kieinert's suture method with both ends of the stitch gathered to one side of the tendon. There are other methods such as Kessler's suture method (FIG. 10D), modified Kessler's suture method (FIG. 11A), Tajima's suture method (FIG. 11B), Pennington's suture method (FIG. 1C) and Becker's suture method (FIG. 1D). Kessler's suture method is similar to Bunuell's suture method except a stitch is not crossed but turned to form a loop. Modified Kessler's suture method is a simplified version of Kessler's suture method. Tajima's suture method is to make both ends K1, K2 of the amputated tendon abutting contact with each other and to suture the tendon with a pair of stitches bound to form a loop inside the tendon with one of the stitches penetrating through the upper point of the center of the abutting contact face perpendicularly and the other penetrating through the under point of the center of the contact face perpendicularly. Pennington's suture method is the same as Kessler's except both ends of a stitch are located on the contact face. Becker's suture method is to overlap each of the ends K1, K2 of the amputated tendon along a longitudinal direction thereof in a given length and to suture the amputated tendon in a given area with a stitch crossed along a longitudinal direction. Becker's suture method is the most reliable for suturing an amputated tendon, however, it takes time. As mentioned above, convalescence after tendon injury has been far improved because of the suturing methods having been developed and devised, however, highly advanced techniques and procedures are still required for an operation of tendon injury. Therefore, tendon injury is still one of the most difficult cases to operate for general surgeons. It has been well-known that an operation of a tendon is difficult, but there is another factor which makes the operation of a tendon difficult. The factor is the sutured portion of the tendon coalesces with its ambient tissue of living organism. Coalescence occurs most of the cases in the process of curing injury regardless of the force by which a tendon is injured, namely, a dull force or a keen knife. If coalescence occurs, the movement of the sutured portion of the tendon is restricted even if the injured portion of the tendon has been cured, thereby to bring about dysfunction.
The above-mentioned surgical procedures are primary intended to minimize coalescence. In order to attain the above-mentioned object various suture methods, surgical apparatus, or materials of a stitch which can prevent coalescence have been developed, improved or suggested. Concretely, several procedures of suturing a tendon have been improved for a primary suture operation. Further procedures of grafting a tendon have been improved, devised for a secondary suture surgery or reconstructive surgery. A method of covering an injured tendon with a material whose primary ingredient is a copolymer of amino acid and polyurethane, a method of covering an injured tendon with the material shaped into a tube (Japanese Patent Laid Open Number 1-124464 "Membrane to prevent coalescence") and a method of wrapping an injured tendon with the material have been suggested.
As mentioned above surgery of a tendon is considered to be difficult. However, treatment and convalescence of injuries of a tendon of a digitus manus have been improved because suture methods, surgical apparatus, or materials of a stitch to prevent coalescence have been developed, improved or suggested. In order to further improve a method of tendon surgery a material which can perfectly prevent coalescence is to be established and the surgery should be conducted by a surgeon of a hand specialist or a fully experienced orthopaedic surgeon who has enough knowledge of the material to prevent coalescence. However, it happens so often that a tendon of a digitus manus gets some injury that all of the cases of injury can not be treated by a fully experienced surgeon. In addition to this, a material which can perfectly prevent coalescence has not yet been established. As a result of this, there are not a few cases that dysfunction is caused after the injury has been cured or that reoperation treatment is required due to unsuitable primary treatment just after injury.
It is an object of the present invention to provide an implant for an injured tendon of a digitus manus which can solve the above-mentioned problem. More specifically, the characteristic of the implant in accordance with the present claimed invention is the material of which the implant is made.